Merge pull request #4 from r0mai/pragma_parse_fix

Fix SIGSEGV in pragma parsing with trailing whitespace
Install clang in CI
Remove unused macros
default_sysinclude removes whitespace from the end of the lines of the output as well.
Move all initial environment detection to one place
Remove unused code
Fix signed/unsigned comparison
Fix signed/unsigned comparison
Remove unused function
Enable C++11
Help CMake find Clang on Windows
Fix include path for the tests on Windows
List of directories checked for clang is written to the error stream instead of stderr
Replace Boost functor with lambda function
Merge remote-tracking branch 'sabel83/master'

Conflicts:
	.travis.yml